Primary cut-out



Aug. 11, 1931. NJ. CONRAD PRIMARY CUT-OUT Filed Aug. 1, 1927 3 Sheets-Sheet l Aug. 11, 1931. N. J. CONRAD PRIMARY CUT-OUT Filed Aug. 1, 1927 3 Sheets-Sheet 5 Patented Aug. 11, 1931 I;;,UN"ITED STATES PATENT OFF-ICE Nicholas J. CONRAD, or WILMETTE, innmoxs, ASSIGNOR, BY mnsnn ASSIGNMENTS, 'ro sonwnrrznn. a CONRAD, me, or CHICAGO, ILPINOIS, a CORPORATION or DELA- WARE v rni uanr cur-our This invention relates to cut-outs, .and more particularly cut-outs adapted. for use in the primary circuits of electrical distribution systems.

In distributing systems the current suptransformer by means of whichcurrent is supplied to the secondary'circuit for use as power or for lighting purposes. There are necessarily a comparatively great number of prlmary transformers in a distributing system which necessitates the use of a large number of cut-outs, each transformer being provided with its individual cut-outs. These cut-outs are commonly mounted upon the cross armsso that the size of the cut-out and its dispositiom'as well as its 'cost are all important considerations. It is also ver desirable that the cut-out itself beqpf slmple construction and so assembled as to permit ready replacement of parts. i

This cut-out is intendedv more particularly as an improvement over the cut-out disclosed in my patent for rimary cut-out, Patent No. 1,466,423 issued ugust 28,1923. While the out-out of my patent is highly satisfactory in many respects, I have found that it is possible to simplify the construction of this cutou'tand to increase its efliciency-from a practical standpoint. It is, of course,,very desira-ble that proper-contact be assured at all times between the cli s in the cut-out and the contact members or errules, and that exces-,

sive spreading of the contact elements of the clips be prevented. With this object I have provided means whereby the contact elements of thefclips are urged inwardly into contact with the contact ferrule, this means also serving'to limit outward movement of the-dip elements beyond normal operative positi n. I have also provideda simplified and less expensive form of fuse structure, as well'as improved means for relieving the fuse' ele-v ment of strain and for securing it to the terminal member whichis operated by the ten-' sion spring. Further objects and advanta es of the improved form of my cut-out wi 1 appear from the detailed description.

In the drawings: Fig. l is a side view of the cut-out mounted on a cross arm-in position for use;

Fig.2 is a' front view of the cut-out in operative position; 7

Fig. 3is a'section taken substantially on llflfle 3-3 of Fig. 2,- the handle being broken 0 a Fig. 4 is a section taken substantially on line 44 of Fig. 3;

Fig. 5 is a section through the handle structure and the-fuse tube and associatedparts taken substantially on line 5-5 of Fig. 6 is a section through-the housing taken substantially on line 6-6 of Fig. 3;

Fig. 7 is a section taken substantially on line 7-7 of Fig. 3;

Fig. 8 is a detail of the connection between the ends of one of the contact clip springs; Fig. 9 is a detail perspective view of the fuse strip; 1

Fig. lO-is a detail face view of the upper portion of the fuse strip; a Fig. 11 is an edge view of the upper portion of the fuse strip partly in section;

,Fig. 12 is a detail-front view of the lower terminal member and associated parts;

. Fig. 13 is a detail side view of the lower terminal member and associated parts;

Fig. 14 is section taken substantially'on line 14-14 of Fig. 12 on an enlarged scale. The cut-out includes a housing 1 in the form of an elongated cylindrical sleeve open at its lower end. This sleeve is provided) intermediate its ends, with spaced circumferentialflanges 2 which define a. recess for the strap portion 3--A of a hanger clamp 3 formed of galvanized steel. Arms 4 extendfrom the ends of-band 3-A and are bent at an inclination to provide fiIigers 5 which are disposed substantially at right angles to arms 4 laterally thereof and are disposed at an obtuse angle upwardly away from the arms 4}, Th fingers are provided i with openings for reception of bolts 6 by means of which the hanger is secured to a cross arm 7 so as to support the sleeve hous- .-ing lat an acute angle downwardly toward the cross arm. As will be noted more clearly from Fig; 3, the lower end of housing 1 is open so that,'by supporting this housing at the inclination illustrated, any gases evolved in the cut-out due to arcing or blowing of the fuse element will be discharged from the lower endof the housing in a direction away from the lineman. This serves to fully protect the lineman against discomfort and possible injury in inserting or removing the fuse structure of the cut-out.

The upper end of the sleeve housing 1 is thickened to provide a reinforcing fiangeS and the bore of the housing is increased slightly in diameter from the upper end thereof to form a recess 9 having an angular shoulder. 10 at its lower end. This recess receives a base ring 11 of a contact. clip 12, the

ring seating upon shoulder 10. The upper face 12A of this ring is of frusto-conical shape to facilitate insertion of the fuse member into the clip. The clip further includes a plurality of resilient contact fingers 12 formed integrally with the base ring 11. This ring and the fingers are preferably formed of brass of proper temper to give to the fingers appreciable resiliency.

The fingers 12 are provided in their outer faces with tranverse shallow recesses or grooves 13 of arcuate shape, these grooves being aligned to form, in effect, a continuous annular chanfiel about the fingers of the contact clip. The grooves 13 receive the inner portion of an elastic member, such as a coil tension 14 which acts by contractile force to urge the fingers 12 inwardly of the clip. This spring is preferably formed of bronze, or any other suitable or preferred material may be used, or the spring may be re laced by a suitable elastic member which will function in the same manner as the spring. In forming the spring a straight coil,' of suitable length is first wound, the

last few turns of this coil at one end, being of reduced diameter so as to thread into the turns at the other end of the coil. The coil is then set into circular shape and the reduced turns threaded into the larger end of the coil and secured in position by soldering or in any other suitable manner. This construction is clearly illustrated in Fig. 8. This provides an annular spring of uniform exterior diameter the ends of which are permanently secured together in such manner as to not interfere with the proper operation of the spring as a contractile member for contracting the contact fingers 12 of the clip.

A second contact clip 15 is mounted in housing 1 remote from clip 12. The clip 15 is similar in construction to clip 12 and includes a base ring 16 and resilient contact fingers 17 projecting therefrom and provided in their outer faces with aligned grooves receiving a tension spring 17' similar to spring 14. The cli 15 is secured in position within the housing liy means of a splitrin 18 formed of spring wire of suitable gauge. This ring is forced into the sleeve housing 1, as at 19, and engages into a groove 20 formed in the outer face of ring 16. The groove 20 is of greater depth than a semi-circle and receives the ring 18 when this ring is completely closed or contracted so that the ring can lie within groove 20 with its outer face flush with outer face of ring '16." The clip 15 is then inserted into the barrel and properly positioned therein, and the ring 18 is-then expanded, thus locking the clip 15 in the housing 1. To expand the ring and prevent displacement of the clip 15, I provide the clip ring 16 with a plurality of locking screws 21a which thread through the ring from .the lower end thereof, these screws being disposed to intersect the groove 20 and con-,, tact with the inner face of-locking ring 18 so as to expand the same into locking engagement with the housing sleeve 1. 'These screws co-act with the ring 19 to positively lock clip 15 in housing sleeve 1 in such manner as. to effectually prevent displacement thereof. This construction will be clear from Figures Q and 7. A lead 21, preferably of the twin or two wire type, is inserted through an opening 22 in flange 8 of housing 1 and the wires 23 of this lead are inserted in a suitable opening in ring 11 and secured therein in any suitable manner as by solder 24. To better accommodate the lead 21 housing 1 is provided, in its outer face, with a groove 25 forming, in. efi'ect, a continuation of the, opening 22. The upper portion of opening 22 is closed by a suitable cement or compound 26 so as to effectually cover the wires 23 andexclud e moisture. This method of connecting the lead is clearly illustrated in Fig. 6. A second lead 27, similar to lead 21, extends through an opening 28 provided in housing 1, adjacent the lower end thereof.

1 This lead is then bent into parallelism with parts so far described are adapted for co- 1 operation with. a plug structure indicated in its entirety by the reference number 33 (Fig. 5). This plug structure includes the haiidle 34 provided at its lower portion with an integral base 35 of cup shape which fits over the upper end of housing 1 and extends downwardly about flange 8, as illustrated in Fig.3. This member thus serves to efl'ectu- .ally prevent the entry of moisture and foreign materials into the housing from the upper end thereof. The handle 34 and base 35, as well as the sleeve housing 1 are molded from an insulation of very high dielectric strength, as well as mechanical strength, which is not affected by the weather. I preferably use for this purpose a product commercially known as Electrdse, though there are several other materials, such as hard porcelain, bakelite or rubber, which would be suitable.

A metallic insert 36, preferably formed of steel or iron, plated or galvanized, is secured in the handle 34 by being molded therein. This insert is suitably bored and threaded for reception of a threaded stud 37 of an upper terminal member 38. This member is formed of a single piece of brass and includes a hexagonal body 39 from the lower end of which extends a reduced threaded neck 40. A reduced tubular element 41 extends from neck and receives the upper end of a tension coil spring 42, the lower end of which fits about a lower terminal member 43. This lower member has its lower portion cut away to provide a semi-cylindrical extension 44 having a flat base 45 (Figs. 12 and 13). A tubular element 46 projects upwardly from the terminal member 44 and receives one end of a stranded copper conductor 47, the other end of which extends into element 41 of the upper terminal member 38. The end portions of the conductor 47 are secured in the elements 41 and 43 by placing such elements in a press and flattening them on the ends of the conductor 47. This conductor is confined within the tension spring 42 and is readily flexible so as to accommodate extension and retraction of the spring. To prevent the ends of the spring from pulling oil of the terminal members, stop pins 48 are spring 42 of any injurious heating1 terial is wound upon the first layers to a re securedin such members, these pins passing through the end turns of the spring. The conductor 47 serves to carry the current flowing through the cut-out and relieves the effects which might result from omitting t e conductor 47 and permitting the current to flow through the spring.

The spring 42 and associated parts are housed in a tube 49. The tube .is preferably constructed of layers of different types. Fiber stock paper is wound on a mandrel to a required thickness, then paper impregnated or coated with raw bakelite or similar maquired thickness. The bakelite or other material is then treated as by baking or hot moulding under pressure, the outer layers becoming a substantially homogenous impregnated mass or layer and the inner layers remaining in their original condition as what is known commercially as fiber. lining 50 imparts mechanical strength to the tube and enables it to better withstand the are as it does not so readily carbonize, as well as the strains incidental to withdrawal and insertion of the plug structure into the housing. The outer impregnated layers render the tube weather and moisture proof and prevents warping and swelling.

A brass ferrule 51 is secured on the upper end of tube 49 and projects beyond the same, the upper end portion of this ferrule being interiorly threaded for co operation with neck 40 of member 38. This provides simple and efficient means for establishing both me- The chanical and electrical connection between greater portion of its diameter beyond the ferrule to provide an extension 53 integral with the ferrule and having a flat face 54. This extension 53 is provided with a threaded hole disposed at right angles to face 54, which hole receives a securing screw 55 on which is threaded a nut 56, the screw and nut ooacting to clamp the lower endof the fuse strip 57 to the lower end of extension 53.

The fuse strip 57 is relatively thin and fiat and is cut away from either side adjacent its upper end to provide a link element 58 which is quickly fusible relative to the body of the strip and is provided, at its central point,

with a slight bend or kink 59. The other end of the fuse strip 57 is secured to portion 44 of terminal member 43 (Figs. 12 and 13). The upper end of strip 57 fits flat against the flat face 45 and is provided with a hole 60 which receives a securing screw, 61 threaded through the element 44. A clamping member or washer 62 bears upon the other face of strip 57 and also has an opening receiving the shank of screw 61, this clamping member being provided with lateral flanges 63 which project across the edges of strip 57 and ex-. tend about the lateral ortions of member 44. Preferably the strip 5 is of less width than face 45 of member 44 (Fig. 12) and the bight portion of member. 62 is provided, adjacent to each corner thereof, with a de res sion forming an inwardly projecting element 64. These elements are disposed to contact with the edges of strip 57 and to align this strip with member 44. A cap or acorn nut 65 is threaded upon screw 61 and bears against the outer face of clamp member 62, the screw and avoid "possibility of turning of member 43,

I provide a stop screw 66 therein which is disposed to contact with the adjacent end of spring 42. e

The fuse strip 57 connects the lower terminal member 43 and the extension 53 of the lower contact fer-rule 52, as clearly illustrated in Figure. 5. When this fuse strip is in operative position the spring 42 is under tension and, unless proper provision were made, this strip would be under v constant tension throughout its whole length including the link element 58. This would be very 0bjectionable as it would subject the link ele-. ment to mechanical strain resulting in variation of'the rating of the fuse element. Also, it would bQlIH ractical to construct a fuse strip having a use element of sufficient mechanical strength to withstand the constant strain of the tension spring as the fuse strip is formed of a relatively soft metal or alloy which does not possess great mechanical strength. While the portion of the strip which is of normal or full width is amply I able to withstand the mechanical strain to the link element 58, which is greatly reduced in width, does not possess the desiredstrength. I have, therefore, provided a strain member which spans the link element 58 and serves to provide a mechanical connection be-.

of this wire being passed through an opening .69 in the strip and wrapped about the projecting end portions of eye 67 after which this eye is beaded and clinched so as to effectually secure the ends of the wire. The eye 671s also clinched so as to avoid any sharp edges against the wire and to effectually secure the eye in the strip. The wire 68 is of such length as to take up all mechanical strain between the eyes 67 and 67. efi'ectually avoiding any strain being transmitted to the link element 58. Wire 68 possesses high mechanical strength and high electrical resistance, this strain member being preferably formed from a suitable length of nickelchromium wire of small gauge. A closure plug 7 0, preferably formed of cork or other suitable heat insulating material is provided with a longitudinally extending slit 71 which snugly receives strip 57, this plug being thus slidably mounted on the strip. Theplug is somewhat greater in length than the fuse element 58 so that, when this plug is in position, it completely encloses the fuse element so as to form an envelop about the same. The plug thus serves to exclude air from the fuse element and is of very material assistance in choking the arc and serves as a barrier when the fuse blows. This plug also serves to protect the fuse element from the atmosphere so as to prevent oxidation and also acts as an insulator to prevent variations in temperature such as would interfere with the rating of the fuse element, to a largeextent. The plug also serves as a reinforcement for the fuse portion to resist bending and twisting. The plug member 70 fits loosely the interior of sleeve 49. In the event the socket member is inserted into the housing when the line is short circuited the gases evolved due to the blowing of the fuse will expel the plug member or cork 70 blowing it out of the lower end of the tube and the housing sweeping the arc out of the tube and quickly killing it and also serving during this operation as an arc barrier between the terminals. which it is subjected by the tension spring,

The ferrules 51 and 52 may be secured to the ends of the tube 49 in any suitable or preferred manner. For this purpose I have shown in Fig. 3, screws 72 which pass through the ferrules and are threaded into the sleeve, these screws being ground ofi flush with the outer faces of the ferrules. For securing the ring 11 of contact clip 12 in the upper end of the sleeve housing 1, I also provide screws 74 which thread through the collar 11 radially thereof, each of these screws being provided with a point 75 which engages into the flange f the housing, these screws co-acting with shoulder 10 to lock the contact clip 11 against movement ineither direction.

The Contact clips 12 and 15 may be of the same or different sizes. Preferably the clip 12 is of. slightly greater interior diameter than the clip 15, the ferrule 52 being of slightly less exterior diameter than ferrule 51. This permits insertion of'the plug structure without any binding action between clip 12 and ferrule 52, facilitating insertion and withdrawal of the plug. The springs 14 and 17 act to contract the resilient contact fingers of the clips so as to insure close contact thereof with the contact .ferrules. The exerior diameter of these contractile springs is such that, if the lower end of the plug structure is inserted into the top contact clip and the ferrules impossible.

accidentally swung sidewise or at an angle ing, said fingers being-movable toward and away from one another radially of the chips,

with the housing, the clip fingers are spread a tension coil spring mounted 'upon the by the contact ferrule so that the spring will contact with the inner wall of the housing and will co-act therein as a'stop member to limit spreading apartof thefingers of the clip beyondvfull operative position. This is advantageous in preventing undue spreading of the" fingers accidentally as would eve tually render close contact thereof with The springs thus act to hold the fingers of the clips in close contact with the ferrules and prevent excessive spreading. l/Vhile I have shown the contact I fingers as provided with grooves or recesses for reception of the inner portions of the spring, these fingers may be otherwise shaped to receive and retain the spring.

- As will be noted more clearly from Fig. 9,

the opening 60 for reception of screw is remote from the lower end of fuse strip 57 This provides a lower portion 57a which projects slightly beyond the lower end of sleeve 49, when this sleeve is screwed onto neck 40 of terminal member 38 with the spring 42 retracted, in assembling. The lower end portion of the strip is then grasped by a pair of pliers and the strip is pulled through the tube to bring opening 60 into alignment with screw 55, and is then moved toward extension 53 to cause the screw to pass through the opening, the strip being then secured in the manner previously described. ,The projectin portion 57 a of strip 57 is then trimmed o as in Fig. 5. The rating of the fuse is preferably impressed in the strip above screw 55, as illustrated. This greatly facilitates assembly of the device and the proper tensioningof the spring 42.

What I claim is v v 1'. In a primary cut-out, a housing, contact clips mounted within the housing in spaced relation, a fused plug member insertible into the housing and having spaced contact members co-operating with the clips, and resilient means normally free of the housing for urging the clips closed and co-acting with the I housing upon expansion of said resilient means to limit opening of the clips.

2. In a primary'cut-out, a housing, contact clips mounted within the housing in spaced relation, a fused plug member insertible into the housing and having spaced contact members co-operating with the clips, and

coiled spring means carried by the clips and urging them closed, said means-being normally free of the housing and co-acting with the housing upon expansion, of said means to limit opening of the clips.

3. In a primary. cut-out," a cylindrical housing, contact clips mounted within the housing in spaced relation and each including a plurality of contact fingers disposed in circul ararrangement concentric with the housgers of each clip and urging them toward each other, said sprin being of a size to contact with the surroun ing wall of the housing and limit spreading apart of the fingers, and a fused plug member insertible into theclips and having contact members coeoperating with said clips. i

4. In a primary cut-out, a housing, contact" clips mounted within the housing inspaced relation and each including a'base ring, and

a plurality of resilient contact fingers secured to the ring concentric therewith and forming v plurality of resilient contact fingers securedto the ring concentric therewith and forming cylindrical contact clips, the fingers bein provided in their outer faces with aligne grooves, a tension coil spring mounted in the groove of the fingers of each clip; and a plug member insertible into-theclips, and having spaced contact members co-operating wit said clips, the convolutions at one end of the spring being reduced in diameter and threaded into and permanently securedto the other end of thespring, the annular spring resulting being of uniform exterior diameter and cooperating with the surrounding wall of the housing to limit spreading apart of the fingers.

6; In a primary cut-out, a housing open at its lower end, spaced contact clips within the housing, a handle structure including a memher for enclosingthe upper end of the housing, an upperterminal-memben secured to said handle structure, a lower terminal memher, a tension spring connecting the terminal members, an insulating tube having end contact ferrules for cooperation with said clips, the ,ferrule at the upper end of the tube having electrical and mechanical connection with the upper terminal member, said tube being inserted through the clips and open a itslower 'end to permit the free passage of. gases therethrough, a'fuse strip connectbers, away from the contact members, said strip being provided with a relatively quickly fusible portion forming a fuse link, anchor members of harder material than the strip securedin said strip beyond the ends of the link portion, and a strain member of relatively great strength and high resistance spanning said link portion and secured at its ends to said anchor members.

8. In a cut-out, a contact member, a terminal member, afuse strip connecting said members, means urging the terminal mem bers away from the contact member, said strip being provided with a relatively quick ly fusible portion forming a fuse link, eyelets of harder material than the strip secured through said strip beyond the ends of the link portion, and a strain member passed through one of the eyelets and having its ends secured about the ends of the other eyelet at opposite sides of the strip.

9. In a cut-out, a terminal member having "a flat face, a fuse strip having a flat end portion seatin% flat against saidfiat face, a clamping mem of the strip and having lateral. flanges extending across the lateral edges of the strip and about the lateral portions of the terminal A member, and means for forcing said clamping member toward the flat face of the terminal member, the clamping member being further providedat each end and adjacent theflanges with projections contacting with the edges of the strip and holding it aligned with the terminal member.

10.'A fuse comprising a strip of fusible material; having a portion intermediate the 'ends thereof of an appreciably reduced cross sectional area, and a strain wire connected to the fuse on the opposite sides ,of said portion and intermediate the ends of the fuse to relieve that portion of tensile strain.

11. A fuse comprising a relatively thin and fiat strip of fusible material having a por tion intermediate the ends thereof of an appreciably reduced cross sectional area, said' strip having a pair of openings on the opposite sidesof said portion and intermediate the ends of thejfuse, and a strain wire connected between the said openings to relieve that portion of the fuse of tensile strain.

In witness whereof, l hereunto subscribe my name this 27th day of July, 1927 NioHoLAs J. CONRAD.

er seating on the end portion 

